Tetranorlanostane and Lanostane Triterpenoids with Cytotoxic Activity from the Epidermis of <i>Poria cocos</i>

Abstract Two unprecedented tetranorlanostane triterpenoids, poricolides A ( 1 ) and B ( 2 ), and two new lanostane triterpenoids, 3 β ‐acetoxy‐24‐methyllanosta‐8,16,24(31)‐trien‐21‐oic acid ( 3 ) and 3 β ‐acetoxylanosta‐7,9(11),16,23‐tetraen‐21‐oic acid ( 4 ), were isolated from the epidermis of Poria cocos . The structures of 1–4 were determined via analysis of 1 H‐, 13 C‐, and 2D‐NMR, and HR‐ESI‐MS data, and the absolute configurations of 1 and 3 were established by single‐crystal X‐ray diffraction analysis. Compounds 1 and 2 were the first report of tetranorlanostane triterpenoid having a δ‐ lactone ring at C(17). Compounds 3 and 4 were rare lanostane triterpenoids having a double bond between C(16) and C(17). Compounds 1–4 exhibited potent antiproliferative effects against A549, SMMC‐7721, MCF‐7, and SW480 cancer cell lines with IC 50 values from 16.19±0.38 to 27.74±1.12 μM.